Why Do Astronauts Use Space Pens Instead of Pencils?

If you’re like me, you were introduced to the idea of the astronaut pen when Jack Klompus gifted one to Jerry Seinfeld on the show Seinfeld, only to have an entire series of mishaps and jokes follow (of course).

Which begs the question…if astronauts need to have special pens to write in zero gravity, why not just use a pencil?

It turns out there’s an answer, and the short one is that pencils are not suited for space travel. They break, shatter, and leave graphite dust behind, not to mention that the wood can pose a fire risk in the oxygen-rich environment. NASA did try mechanical pencils first, but at $128 each, they weren’t a reasonable alternative.

Enter the Space Pen, invented by Paul Fisher, the head of Fisher Pen Company, in 1965. It uses compressed nitrogen to force ink from the nozzle as opposed to the gravity it uses on earth – which means it writes upside down, just like Jack Klompus said.

NASA was impressed with the tech and the Fisher Space Pens made their debut in 1968 on the Apollo 7 mission, and have gone into space on every mission since.